subroutine init_global_param
  use global_param
  implicit none

  ! elementary point defect
  n_point_type=0
  nullify(pdefect)

  ! Number of the types of the external events
  n_ext=0
  nullify(extern_type)

  ! Default unit for output
  out_unit=1

  ! Default user seed
  user_seed=-1
  
  ! Pre-calculated parameter
  isqrt3=1.0/sqrt(3.0)

  return

end subroutine init_global_param
